I know the regular amf.com site is up and working.  Though amf300.com has always been separate and I also had connection problems when trying it out.

I noticed this yesterday as well early in the afternoon. I would believe it is server maintenance or some work being done to the site. Their site recently got a make over within the last 6 months to a year. Their archive information said "under construction" after the make over. Maybe they are simply updating the site. At any rate, I don't think it will be down for long.

Understood. As of Friday morning 10:30 AM Eastern still not connectable.
Which is another problem. If they're working on the site or the server, you should get a message saying what they're doing and a time estimate for when it will return. If I did that when I was working, I wouldn't have been working there very long. It's a poke in the eye with a sharp stick to your supporters and customers, telling them you really don't care about them.

It could be that they don't have any redundancy in case of down time.